You can find an Oshiwambo dictionary and you can also find an Oshindonga dictionary. But you can't find any for Oshikwanyama, or at least I didn't. Even the ones existing for other Owambo languages are just available as a paper copy. Now instead of buying a book, which you have to carry around all day long, just get the portable version in form of an app! The best part is, even though they speak different languages in the different Regions of Namibia, thanks to the similarity of these language